1. Field of the Invention
This invention relates to tire valves having tubular plastic inserts. More specifically, this invention relates to plastic tire valves having a minimum of parts and which maximize the flow of air through the valve during filling and discharging operations.
2. Description of the Prior Art
In the prior art, there have been disclosures of tire valves having plastic tubular inserts. An example is shown in U.S. Pat. No. 3,741,267 which issued June 26, 1973 to Stephen Thacker and which is assigned to the assignee of the present application. In such earlier disclosures, however, the plastic molded insert, while providing integral means for guiding the valve pin, did not truly maximize the possible air flow through the valve during filling or discharging operations. Moreover, such earlier disclosures required structure with elaborate valve element biasing means.
Another example of an eariler plastic valve structure is found in the U.S. Pat. No. 3,032,091 which issued May 2, 1962 to McCord. In such earlier arrangements, however, an inner annular flange in the plastic insert closely surrounds and guides the valve pin and seriously limits air flow through the valve.
Simple valve structures have been disclosed in tire valves in the prior art, though not in plastic tire valve structures. An example is shown in the old U.S. Pat. No. 2,260,646 which issued Oct. 28, 1941 to Sorokin. Such earlier structures include spring means surrounding the pin and above the valve seat to bias the valve closed.